Phonon-assisted optical absorption in silicon from first principles

Area of Science:

• Solid State Physics
• Materials Science
• Computational Physics

Background:

• Understanding optical absorption in silicon is crucial for optoelectronics.
• Existing models struggle to accurately predict absorption spectra, especially in the visible range.

Purpose of the Study:

• To develop a first-principles method for calculating silicon's phonon-assisted optical absorption spectrum.
• To accurately model visible-range absorption for optoelectronic and photovoltaic applications.

Main Methods:

• Utilized quasiparticle calculations.
• Employed Wannier interpolation for Brillouin zone grids.
• Determined quasiparticle energies, optical transition, and electron-phonon coupling matrix elements.

Main Results:

• Achieved excellent agreement with experimental data for indirect absorption onset across temperatures.
• Accurately predicted the optical absorption spectrum in the visible range.
• Demonstrated the method's capability beyond simple models.

Conclusions:

• The developed first-principles approach accurately captures phonon-assisted optical absorption in silicon.
• This method is applicable to various materials and phonon-assisted processes.
• Provides a robust tool for designing silicon-based optoelectronic devices.